Morata met up with Spain on Sunday, where an MRI scan at the Sanitas University Hospital of La Moraleja in Madrid diagnosed "a grade II myofascial injury in the hamstring muscles", the Spanish Football Federation said.

He was immediately ruled out of Spain's World Cup qualifiers with Albania and Israel, and Chelsea will conduct their own tests once the striker returns to London.

The Blues, six points behind Premier League leaders City, next play on October 14 at Crystal Palace in the first of six games in 18 days.

Morata has scored seven goals since signing for £58million from Real Madrid as a direct replacement for Diego Costa, now at Atletico Madrid.

His possible absence will give Michy Batshuayi an opportunity, if Conte selects the Belgian who has netted five times this season, including the winner at Atletico last week.

A month-long absence for Morata could impact Chelsea's Champions League hopes - two of the six games before the end of October are against Roma - but the other matches are more favourable.

As well as winless and scoreless Palace, Chelsea face Watford and Bournemouth in the Premier League, plus Everton in the Carabao Cup fourth round.